Selection of dosage: For reference, in adults with ALS, riluzole was safe and effective in dosages of 100 and 200 mg twice daily. In a treatment study of infants with spinal muscular atrophy the maximum dosage was 10 mg higher than a 107 mg/m2 dose, e.g., for a 5 kg child whose surface area was 0.33 m2 , the dose was 35 mg/day. No child had any change in laboratory studies or had adverse effects.